Heteropolyacid and or its salt supported catalyst, production process of the catalyst and production process of compound using the catalyst

ABSTRACT

A supported catalyst comprising a support having supported thereon at least one member selected from the group consisting of heteropolyacids and heteropolyacid salts, in which the heteropolyacid and/or heteropolyacid salt is substantially present in a surface layer region of the support to a depth of 30% from the support surface. The catalyst has a high performance when used for the production of compounds by various reactions.

CROSS-REFERENCE TO RELATED APPLICATION

This application is an application filed under 35 U.S.C. § 111(a)claiming benefit pursuant to 35 U.S.C. § 119(e)(1) of the filing date ofthe Provisional Application 60/436,633 filed Dec. 30, 2002, pursuant to35 U.S.C. § 111(b).

TECHNICAL FIELD

The present invention relates to a supported catalyst comprising asupport having supported thereon a hetero-polyacid and/or aheteropolyacid salt as one of the catalyst components, wherein theheteropolyacid and/or heteropolyacid salt supported is substantiallypresent in a fixed region on the support surface. The present inventionalso relates to a production process of the catalyst and a process forproducing a compound by using the catalyst.

In particular, the supported catalyst of the present invention is usefulas a catalyst for the production of a lower aliphatic carboxylic acid bya single-stage contact reaction of a lower olefin and oxygen, or as acatalyst for the production of a lower aliphatic carboxylic acid esterby a reaction of a lower olefin and a lower aliphatic carboxylic acid.

BACKGROUND ART

Heteropolyacids are well known to be useful as acid catalysts oroxidation catalysts. A heteropolyacid and/or heteropolyacid saltsupported on a support can prevent the elution of the heteropolyacid orthe precipitation of carbonaceous material or increase the surface areato elevate the efficiency in a reaction with a substrate having lowaffinity for the heteropolyacid. Therefore, the catalyst using aheteropolyacid and/or a heteropolyacid salt as the effective componentis generally used as a supported catalyst where the heteropolyacidand/or heteropolyacid salt is supported on a porous support such assilica.

The supported state of the catalyst component in the supported catalystincludes several types. Specific examples thereof include a uniformtype, an egg shell type (skin type) and an egg white type. The uniformtype, egg shell type and egg white type as used herein each means asupported catalyst in the following state (see, Yoshio ONO et al.,Shokubai no Jiten (Dictionary of Catalyst), 1st ed., 1st imp. pages 102,108 and 585, Asakura Shoten (Nov. 1, 2000)).

Uniform Type:

So-called uniform distribution or uniform loading.

Egg Shell Type:

This is one of active component distribution states in a supportparticle or molded body of a supported catalyst and means a state wherethe active component is present only on the outer surface of the supportparticle or molded body.

Egg White Type:

This is one of active component distribution states in a supportparticle or molded body of a supported catalyst and means a state wherethe active component is present in an inner layer of the support.

The heteropolyacid and/or heteropolyacid salt is used as a supportedcatalyst, for example, in the hydration of an olefin (see, JapaneseUnexamined Patent Publication No. 11-322646 (JP-A-11-322646)) theproduction of a carboxylic acid ester (see, Japanese Unexamined PatentPublication Nos. 11-263748 and 9-118647 (JP-A-11-263748 andJP-A-9-118647)) and the production of an acetic acid by ethyleneoxidation (see, Japanese Unexamined Patent Publication No. 7-89896(JP-A-7-89896)).

Heretofore, the heteropolyacid and/or heteropolyacid salt has beengenerally supported in the uniform type. However, the uniform type has aproblem that, particularly in a surface-type reaction using thediffusion of raw material as a rate-determining factor, theheteropolyacid and/or heteropolyacid salt supported inside the supportmay not efficiently participate in the reaction.

On the other hand, as for the method for loading a heteropolyacid in thestate other than the uniform type, U.S. Pat. No. 5,919,725 discloses amethod of loading a heteropolyacid salt in a specific position slightlyinside the surface (so-called egg white type). However, theheteropolyacid salt in the egg white-type catalyst is present inside thesupport and, in a surface-type reaction of using the diffusion of rawmaterial as a rate-determining factor, cannot make efficient contactwith a reactant.

To solve this problem, a catalyst where the heteropolyacid and/orheteropolyacid salt is supported on the surface (so-called egg shelltype or skin type) is considered to be more effective.

Particularly, in an oxidation reaction which is a surface-type reaction,it is important to load the catalyst component in the vicinity ofsurface. For example, JP-A-7-89896 discloses a method of synthesizing anacetic acid from ethylene and oxygen in the presence of a catalystcontaining (a) metal palladium and (b) at least one compound selectedfrom heteropolyacids and salts thereof. According to this method, thepalladium metal interacts with the heteropolyacid and/or heteropolyacidsalt to exert very high activity and selectivity and thereby exhibitexcellent activity and selectivity for the production of an acetic acid.

In this example, it is presumed that the metal palladium is supported inthe egg shell-type state and the heteropolyacid and/or heteropolyacidsalt is, in view of its general loading method on a support, supportedin the uniform type. Also in this case, the use efficiency is consideredto be elevated by loading the heteropolyacid and/or heteropolyacid saltin the egg shell-type state. Furthermore, when both the metal palladiumand the heteropolyacid and/or heteropolyacid salt are supported in theegg shell-type state, these two members can be made present veryadjacently and this seems to bring about increase in the probability ofinteraction and, in turn, production of a higher performance catalyst,In addition, by loading the heteropolyacid and/or heteropolyacid salt inthe egg shell-type state, the absolute amount of heteropolyacid and/orheteropolyacid salt can be decreased as compared with the uniform typeand this is advantageous in view of profitability and reduction in thecost for recovery and reproduction.

However, a catalyst where a heteropolyacid and/or a heteropolyacid saltis supported in the egg shell-type state, and a production process ofthe catalyst have been heretofore unknown.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a heteropolyacid-and/or heteropolyacid salt-supported catalyst having a higherperformance, which is used for the production of a compound by variousreactions, particularly by a surface reaction.

Another object of the present invention is to provide a productionprocess of the catalyst and a process for producing a compound by usingthe catalyst.

As a result of extensive investigations for a heteropolyacid- and/orheteropolyacid salt-supported catalyst used in the production of acompound by various reactions, particularly by a surface reaction, whichensures efficient contact of the heteropolyacid and/or heteropolyacidsalt with a reaction substrate and thereby exhibits higher performance,the present inventors have found that when the heteropolyacid and/orheteropolyacid salt, as an active component of the catalyst, issupported in the egg shell-type state, a higher performance catalyst canbe obtained. The present invention has been accomplished based on thisfinding.

More specifically, the present invention (I) is a supported catalystcomprising a support having supported thereon one member selected fromthe group consisting of heteropolyacids and heteropolyacid salts,wherein the at least one heteropolyacid and/or heteropolyacid salt issubstantially present in the surface layer region to a depth of 30% fromthe support surface.

The present invention (II) is a production process of the supportedcatalyst of the present invention (I).

The present invention (III) is a process for producing a compound byusing the supported catalyst of the present invention (I).

Furthermore, the present invention comprises, for example, the followingmatters.

[1] A supported catalyst comprising a support having supported thereonat least one member selected from the group consisting ofheteropolyacids and heteropolyacid salts, wherein the heteropolyacidand/or heteropolyacid salt is substantially present in the surface layerregion to a depth of 30% from the support surface.

[2] The catalyst as described in [1] above, wherein 90 mass % or more ofthe heteropolyacid and/or heteropolyacid salt is present in the surfacelayer region to a depth of 30% from the support surface.

[3] The catalyst as described in [1] or [2] above, wherein theheteropolyacid is at least one member selected from the group consistingof silicotungstic acid, phosphotungstic acid, phosphomolybdic acid,silicomolybdic acid, silicovanadotungstic acid, phosphovanadotungsticacid, phosphovanadomolybdic acid, silicovanadomolybdic acid,phosphomolybdotungstic acid, silicomolybdotungstic acid,silicovanadotungstic acid, borotungstic acid, boromolybdic acid andtungstomolybdoboric acid.

[4] The catalyst as described in any one of [1] to [3] above, whereinthe heteropolyacid salt is either an onium salt of a heteropolyacid or asalt resulting from partially or entirely substituting hydrogen atoms ofa heteropolyacid by at least one element selected from metal elementsbelonging to Groups 1 to 13 in the Periodic Table (Revised Edition ofIUPAC Inorganic Chemistry Nomenclature (1989)), and the heteropolyacidis selected from the group consisting of silicotungstic acid,phosphotungstic acid, phosphomolybdic acid, silicomolybdic acid,silicovanadotungstic acid, phosphovanadotungstic acid,phosphovanadomolybdic acid, silicovanadomolybdic acid,phosphomolybdotungstic acid, silicomolybdotungstic acid,silicovanadotungstic acid, borotungstic acid, boromolybdic acid andtungstomolybdoboric acid.

[5] The catalyst as described in any one of [1] to [4] above, whereinthe support is at least one member selected from the group consisting ofsilica, diatomaceous earth, montmorillonite, titania, activated carbon,silica alumina, alumina, magnesia, niobia and zirconia.

[6] The catalyst as described in any one of [1] to [5] above, whereinthe particle size of the support is from 0.5 to 50 mm.

[7] The catalyst as described in any one of [1] to [6] above, whereinthe specific surface area of the support is from 10 to 500 m²/g and thepore volume is from 0.1 to 3.0 ml/g.

[8] A process for producing the supported catalyst described in any oneof [1] to [7] above, comprising the following first to third steps:

First Step:

a step of dissolving a heteropolyacid and/or a heteropolyacid salt in asolvent corresponding to 10 to 40 vol % of the liquid absorption amountof a support to obtain a heteropolyacid and/or heteropolyacid saltsolution having a kinematic viscosity of 2.0 to 15.0 cSt (at 40° C.);

Second Step:

a step of impregnating a support with the heteropolyacid and/orheteropolyacid salt solution obtained in the first step to obtain aheteropolyacid and/or heteropolyacid salt-impregnated support; and

Third Step:

a step of drying the heteropolyacid and/or heteropolyacidsalt-impregnated support obtained in the second step to obtain aheteropolyacid and/or heteropolyacid salt-supported catalyst.

[9] The process as described in [8] above, wherein the solvent is apolar solvent.

[10] The process as described in [9] above, wherein the polar solvent isany one of a lower aliphatic carboxylic acid, a lower aliphatic alcoholor a mixture thereof.

[11] A process for producing a compound, comprising performing areaction in the presence of the supported catalyst described in any oneof [1] to [7] above.

[12] The process as described in [11] above, wherein the reaction is atleast one reaction selected from the group consisting of anisomerization reaction, an oxidation reaction, a hydration reaction, adehydrogenation reaction, an ether-producing reaction, an esterificationreaction, a conversion reaction, an acylation reaction, a Ritterreaction and an alkylation reaction.

[13] The process as described in [11] or [12] above, wherein a loweraliphatic olefin and an oxygen are reacted to produce a lower aliphaticcarboxylic acid.

[14] The process as described in [13] above, wherein the reaction isperformed in the presence of water.

[15] The process as described in [11] or [12] above, wherein a lowerolefin and a lower aliphatic carboxylic acid are reacted to produce alower aliphatic carboxylic acid ester.

[16] The process as described in [15] above, wherein the reaction isperformed in the presence of water.

[17] A lower aliphatic carboxylic acid produced by the process describedin [13] or [14] above.

[18] A lower aliphatic carboxylic acid ester produced by the processdescribed in [15] or [16] above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a spherical support; A is a longdiameter line in the cross section and B is a midpoint of the longdiameter line.

FIG. 2 is a perspective view of a cylindrical support; the line ab is aline of giving a maximum diameter of the circle (C).

FIG. 3 is a cross-sectional view when the cylindrical support of FIG. 2is cut at the line ab; D is a long diameter line in this cross section,E is a short diameter line and F is a midpoint of the long diameterline.

FIG. 4 is a perspective view of a prismatic support; the line cd is aline cutting the support from the midpoint (J) of the side (H) inparallel to the side (I) when the face (G) is a square, and a linecutting the support from the midpoint (J) of the long side (H) inparallel to the short side (I) when the face (G) is a rectangle.

FIG. 5 is a cross-sectional view when the prismatic support of FIG. 4 iscut at the line cd; L is a long diameter line in this cross section, Mis a short diameter line and N is a midpoint of the long diameter line.

FIG. 6 is a cross-sectional view of a cocoon-like support; O is a longdiameter line in this cross section, P is a short diameter line, Q is amidpoint of the long diameter line and R is a midpoint of the shortdiameter line.

FIG. 7 is a perspective view of a pipe-like support; the line ef is,similarly to the cylindrical support, a line of giving a maximumdiameter of the circle (S).

FIG. 8 is a cross-sectional view when the pipe-like support of FIG. 7 iscut at the line ef.

FIG. 9 is an enlarged view of the cross-sectional view of FIG. 8; T is along diameter line in this cross section, U is a short diameter line andV is a midpoint of the long diameter line.

BEST MODE FOR CARRYING OUT THE INVENTION

The preferred embodiments of the present invention are described below.

The “surface layer region to a depth of 30% from the support surface” asused in the present invention (I) varies depending on the shape ofsupport used but follows, for example, the definitions below.

(1) In the Case of Spherical Support

The region means a region covering a distance from the support surfaceto 30% toward the midpoint in a cross section (FIG. 1) cut to give amaximum area.

(2) In the Case of Cylindrical Support

The region means a region covering a distance from the support surfaceto 30% toward the inside of support in a cross section (FIG. 3) obtainedby cutting the line ab (FIG. 2).

(3) In the Case of Prismatic Support

The region means a region covering a distance from the support surfaceto 30% toward the inside of support in a cross section (FIG. 5) obtainedby cutting the line cd (FIG. 4).

(4) In the Case of Cocoon-Like Support

The region means a region covering a distance from the support surfaceto 30% toward the inside of support in a cross section (FIG. 6) cut togive a maximum area.

(5) In the Case of Pipe-Like Support

The region means a region covering a distance from the support surfaceto 30% toward the inside of support in a cross section (FIGS. 8 and 9)obtained by cutting the line ef (FIG. 7).

In the case of a support having a shape not similar to any of theseshapes, similarly to those supports, the region indicates a portion inthe range covering a distance from the surface to 30%.

In the supported catalyst of the present invention, in view of activity,the heteropolyacid and/or heteropoly-acid salt is preferably present ina larger amount in a portion closer to the support surface. Accordingly,the region where the heteropolyacid and/or heteropolyacid salt exists ispreferably closer to the surface and this is preferably a region of 25%,more preferably 20%, from the surface.

The “substantially present in the surface layer region” as used in thesupported catalyst of the present invention (I) means such a state that,when the distribution state of heteropolyacid and/or heteropolyacid saltin the supported catalyst is examined, for example, by an analysismethod which is described later, the amount of hetero-polyacid and/orheteropolyacid salt is lower than the detection limit in the regionexcept for the specified surface layer region.

Not all heteropolyacid and/or heteropolyacid salt needs to be present inthe surface layer region but if the distribution has a gradient to acertain degree, the purpose as the supported catalyst of the presentinvention (I) can be achieved. The gradient of the distribution ispreferably such that 90 mass % or more, preferably 95 mass % or more,more preferably 98 mass % or more of the entire heteropolyacid and/orheteropolyacid salt contained in the catalyst is present in the surfacelayer region to a depth corresponding to 30% of the radius drawn fromthe support surface to the center.

In the supported catalyst of the present invention (I), the method fordetermining the supported distribution of heteropolyacid and/orheteropolyacid salt is not particularly limited and any known method maybe used. For example, with respect to the simpler presence ofhetero-polyacid and/or heteropolyacid salt, in the case of a coloredheteropolyacid and/or heteropolyacid salt, the distribution can bemeasured by eye. The phosphotungstic acid and silicotungstic acid eachis white but is colored by a heat treatment at about 400° C. or more andtherefore, such a heteropolyacid may be colored by the heat treatmentand the distribution measured by eye.

As for the method of quantitatively measuring the distribution, ameasurement, for example, by an electron probe microanalyzer(hereinafter referred to as “EPMA”) is preferred. The EPMA as usedherein is a device of irradiating a solid substance with an electronprobe stopped down to a micron order and performing the elementalanalysis or observing the form by utilizing the characteristic X-ray,reflected electron, secondary electron or the like generated from themicrofine portion. The EPMA is described in detail in Tsuguro Kinouchi,EPMA Electron Probe Microanalyzer, 1st ed., 1st imp., Gijutsu Shoin(Mar. 30, 2002).

The supported distribution of heteropolyacid and/or heteropolyacid saltin the supported catalyst of the present invention is determined byusing EPMA according to the following methods. Incidentally, as for thedistribution of heteropolyacid and/or heteropolyacid salt, thedistribution of tungsten or molybdenum element is measured according tothe kind of heteropolyacid supported and this is regarded as thedistribution of the corresponding heteropolyacid and/or heteropolyacidsalt.

Plane Analysis:

The measurement conditions for the plane analysis are determined by thepeak search and the measurement is performed by the plane analysis ofthree patterns, that is, crystal position of the peak top obtained bythe peak search and for the consideration of background, crystalpositions shifted before and after the crystal position of the peak top.Based on the measured values, an operation is performed by takingaccount of the background to obtain plane analysis data. The operationis performed according to the following formula:Plane analysis date=S−(BG1+BG2)/2wherein S is an intensity measured at the crystal position of peak topobtained by the peak search and BG1 (background 1) and BG2 (background2) are intensities at respective measuring points shifted before andafter the crystal position of peak top.

Line Analysis:

As the post-treatment of plane analysis data, intensity data for anarbitrary support diameter are taken out to obtain an X-ray intensityprofile. The X-ray intensity profile obtained by the line analysis isapproximated (corresponds) to the element concentration and therefore,the supported distribution is determined by integrating the X-rayintensity profiles.

The supported distribution of heteropolyacid and/or heteropolyacid saltis determined by using the following method according to the shape ofsupport.

In the Case of Spherical Support:

(1) Assuming that the support shape is a true sphere, the support is cutto a cross section of giving a maximum area (FIG. 1).

(2) The cross section is subjected to plane analysis by EPMA and fromthe plane analysis data, intensity profile data on the long diameterline A are obtained.

(3) From the intensity profile data, the entire integral intensity fromthe support surface to the midpoint (B) and the entire integralintensity from the support surface to 30% are calculated.

(4) From the ratio of entire integral intensities determined in (3), thesupported distribution is calculated.

In the Case of Cylindrical Support:

(1) Assuming that the support shape is a true cylinder, the support iscut at the line ab of giving a maximum diameter of a circle C (FIG. 2).

(2) The cross section is subjected to plane analysis by EPMA and fromthe plane analysis data, intensity profile data on the long diameterline D and on the short diameter line E are obtained (FIG. 3). In thiscase, the short diameter line E is a straight line crossing, at rightangles, the midpoint F of the long diameter line D.

(3) From the intensity profile data, the entire integral intensity fromthe support surface to the midpoint F and the entire integral intensityfrom the support surface to 30% are calculated on each of the longdiameter line D and the short diameter line E.

(4) From the entire integral intensities determined in (3), thesupported distribution on each diameter line is calculated.

In the Case of Prismatic Support:

(1) When the face G is a square, the support is cut at the line cd fromthe midpoint J of the side H in parallel to the side I (FIG. 4). Whenthe face G is a rectangle, the support is cut at the line cd from themidpoint J of the long side H in parallel to the short side I (FIG. 4).

(2) The cross section is subjected to plane analysis by EPMA and fromthe plane analysis data, intensity profile data on the long diameterline L and on the short diameter line M are obtained (FIG. 5). In thiscase, the short diameter line M is a straight line right-angle crossingthe midpoint N of the long diameter line L

(3) From the intensity profile data, the entire integral intensity fromthe support surface to the midpoint N and the entire integral intensityfrom the support surface to 30% are calculated on each of the longdiameter line L and the short diameter line M.

(4) From the entire integral intensities determined in (3), thesupported distribution on each diameter line is calculated.

In the Case of Cocoon-Like Support:

(1) The support is cut to a cross section of giving a maximum area (FIG.6).

(2) The cross section is subjected to plane analysis by EPMA and fromthe plane analysis data, intensity profile data on the long diameterline O and on the short diameter line P are obtained. The midpoint ofthe long diameter line O is designated as Q and the midpoint of theshort diameter line P is designated as R.

(3) From the intensity profile data, the entire integral intensity fromthe support surface to the midpoint Q of the long diameter line O andthe entire integral intensity from the support surface to 30% arecalculated on the long diameter line O. Similarly to the long diameterline O, the entire integral intensity from the support surface to themidpoint R and the entire integral intensity from the support surface to30% are calculated on the short diameter line P.

(4) From the entire integral intensities determined in (3), thesupported distribution on each diameter line is calculated.

In the Case of Pipe-Like Support:

(1) Assuming that the support is a cylindrical support, the support iscut at the line ef of giving a maximum diameter of a circle S similarlyto the cylindrical support (FIG. 7).

(2) The cross section is subjected to plane analysis by EPMA and fromthe plane analysis data, intensity profile data on the long diameterline T and on the short diameter line U are obtained (FIGS. 8 and 9). Inthis case, the short diameter line U is a straight line crossing, atright angles, the midpoint V of the long diameter line T.

(3) From the intensity profile data, the entire integral intensity fromthe support surface to the midpoint V and the entire integral intensityfrom the support surface to 30% are calculated on each of the longdiameter line T and the short diameter line U.

(4) From the entire integral intensities determined in (3), thesupported distribution on each diameter line is calculated.

As an example of the calculation of supported distribution, thesupported distribution of a spherical support is determined according tothe following formulae:V ₁=(4/3)π(A/2)³  (1)V ₂=(4/3)π(0.7(A/2))³  (2)V ₃ =V ₁ −V ₂  (3)Wc=(I ₂ V ₃/(I ₁ V ₂ +I ₂ V ₃))×100  (4)wherein (A/2) is a radius (mm) of the support, π is a ratio of thecircumference of a circle to its diameter, V₁ is an entire volume (mm³)of the support, V₂ is a volume (mm³) of the support in the region fromthe support center to 70% of the radius, V₃ is a volume (mm³) of thesupport in the region from the support surface to 30% of the radius, Wcis a percentage (%) of heteropolyacid and/or heteropolyacid saltsupported in the region from the support surface to 30% of the radius,I₁ is an integral intensity of the X-ray profile from the support centerto 70% of the radius obtained by the line analysis, and I₂ is anintegral intensity of an X-ray profile from the support surface to 30%of the radius obtained by the line analysis.

The heteropolyacid which can be used for the production of the supportedcatalyst of the present invention comprises a center element and aperipheral element to which oxygen is bonded. The center element isusually silicon or phosphorus but may be one arbitrary element selectedfrom various elements belonging to Groups 1 to 17 of the Periodic Table(Revised Edition of IUPAC Inorganic Chemistry Nomenclature (1989)).Specific examples thereof include cupric ion; divalent beryllium, zinc,cobalt and nickel ions; trivalent boron, aluminum, gallium, iron,cerium, arsenic, antimony, phosphorus, bismuth, chromium and rhodiumions; tetravalent silicon, germanium, tin, titanium, zirconium,vanadium, sulfur, tellurium, manganese, nickel, platinum, thorium,hafnium and cerium ions and other rare earth ions; pentavalentphosphorus, arsenic, vanadium and antimony ions; hexavalent telluriumion; and heptavalent iodide ion, however, the present invention is notlimited thereto. Specific examples of the peripheral element includetungsten, molybdenum, vanadium, niobium and tantalum. However, thepresent invention is not limited thereto.

These heteropolyacids are also known as a “polyoxoanion”,“polyoxometallic salt” or “metal oxide cluster”. The structures of somewell-known anions are named after the researcher in this field andcalled, for example, Keggin, Wells-Dawson or Anderson-Evans-Perloffstructure. These are described in detail in Poly-San no Kagaku, KikanKagaku Sosetsu (Chemistry of Polyacid, Quarterly of Chemistry Review),No. 20, compiled by Nippon Kagaku Kai (1993). The heteropolyacid usuallyhas a high molecular weight, for example, a molecular weight of 700 to8,500, and includes not only the monomers but also dimeric complexesthereof.

The method for synthesizing the heteropolyacid for use in the supportedcatalyst of the present invention (I) is not particularly limited andany method may be used. For example, the heteropolyacid can be obtainedby heating an acidic aqueous solution containing a salt of molybdic acidor tungstic acid and a simple oxygen acid of hetero atom or a saltthereof (pH: about 1 to 2). For isolating the heteropolyacid compoundfrom the aqueous heteropolyacid solution produced, a method ofcrystallizing and separating the compound in the form of a metal saltmay be used. Specific examples thereof include those described in ShinJikken Kagaku Koza 8, Muki Kagoubutsu no Gosei (III) (New ExperimentalChemistry Course 8, Synthesis of Inorganic Compounds (III)), 3rd ed.,page 1413, compiled by Nippon Kagaku Kai, issued by Maruzen (Aug. 20,1984), however, the present invention is not limited thereto. The Kegginstructure of the heteropolyacid synthesized can be identified by thechemical analysis or by the X-ray diffraction or UV or IR measurement.

Specific examples of the heteropolyacid include:

silicotungstic acid H₄[SiW₁₂O₄₀]•xH₂O phosphotungstic acidH₃[PW₁₂O₄₀]•xH₂O phosphomolybdic acid H₃[PMo₁₂O₄₀]•xH₂O silicomolybdicacid H₄[SiMo₁₂O₄₀]•xH₂O silicovanadotungstic acidH_(4+n)[SiV_(n)W_(12−n)O₄₀]•xH₂O phosphovanadotungstic acidH_(3+n)[PV_(n)W_(12−n)O₄₀]•xH₂O phosphovanadomolybdic acidH_(3+n)[PV_(n)Mo_(12−n)O₄₀]•xH₂O silicovanadomolybdic acidH_(4+n)[SiV_(n)Mo_(12−n)O₄₀]•xH₂O silicomolybdotungstic acidH₄[SiMo_(n)W_(12−n)O₄₀]•xH₂O phosphomolybdotungstic acidH₃[PMo_(n)W_(12−n)O₄₀]•xH₂O(wherein n is an integer of 1 to 11 and x is an integer of 1 or more).However, the present invention is not limited thereto.

Among these, preferred are silicotungstic acid, phosphotungstic acid,phosphomolybdic acid, silicomolybdic acid, silicovanadotungstic acid andphosphovanadotungstic acid, more preferred are silicotungstic acid,phosphotungstic acid, silicovanadotungstic acid andphosphovanadotungstic acid.

The heteropolyacid salt which can be used in the production of thecatalyst of the present invention may be a salt resulting from partiallyor entirely substituting hydrogen atoms of the above-describedheteropolyacid by at least one element selected from metal elementsbelonging to Groups 1 to 13 in the Periodic Table (Revised Edition ofIUPAC Inorganic Chemistry Nomenclature (1989)), or an onium salt of theheteropolyacid. Specific examples thereof include metal salts such aslithium, sodium, magnesium, barium, copper, gold, palladium and gallium,and onium salts, however, the present invention is not limited thereto.Among these, lithium salt, sodium salt, gallium salt, copper salt, goldsalt and palladium salt are preferred, and lithium salt, sodium salt,copper salt and palladium salt are more preferred.

Examples of the starting material for the element of forming theheteropolyacid salt include lithium nitrate, lithium acetate, lithiumsulfate, lithium sulfite, lithium carbonate, lithium phosphate, lithiumoxalate, lithium nitrite, lithium chloride, lithium citrate, sodiumnitrate, sodium acetate, sodium sulfate, sodium carbonate, monosodiumphosphate, disodium phosphate, sodium oxalate, sodium nitrite, sodiumchloride, sodium citrate, magnesium nitrate hexahydrate, magnesiumacetate tetrahydrate, magnesium sulfate, magnesium carbonate, magnesiumphosphate tricosahydrate, magnesium oxalate dihydrate, magnesiumchloride, magnesium citrate, barium nitrate, barium acetate, bariumsulfate, barium carbonate, barium hydrogenphosphate, barium oxalatemonohydrate, barium sulfite, barium chloride, barium citrate, coppernitrate, copper acetate, copper sulfate, copper carbonate, copperdiphosphate, copper oxalate, copper chloride, copper citrate, aurouschloride, chloroauric acid, auric oxide, auric hydroxide, auric sulfide,aurous sulfide, palladium nitrate, palladium acetate, palladium sulfate,palladium chloride, gallium dichloride, gallium monochloride, galliumcitrate, gallium acetate, gallium nitrate, gallium sulfate, galliumphosphate, ammonium acetate, ammonium carbonate, ammonium nitrate,ammonium dihydrogenphosphate, ammonium hydrogen-carbonate, ammoniumcitrate, ammonium nitrate, diammonium phosphate, monoammonium phosphateand ammonium sulfate. However, the present invention is by no meanslimited thereto.

Among these, preferred are lithium nitrate, lithium acetate, lithiumcarbonate, lithium oxalate, lithium citrate, sodium nitrate, sodiumacetate, sodium carbonate, sodium oxalate, sodium citrate, coppernitrate, copper acetate, copper carbonate, copper citrate, aurouschloride, chloroauric acid, palladium nitrate, palladium acetate,gallium citrate, gallium acetate and gallium nitrate, and more preferredare lithium nitrate, lithium acetate, lithium carbonate, lithiumoxalate, lithium citrate, sodium nitrate, sodium acetate, sodiumcarbonate, sodium oxalate, sodium citrate, copper nitrate, copperacetate, copper carbonate, copper citrate, palladium nitrate andpalladium acetate.

Specific examples of these heteropolyacid salts include lithium salt ofsilicotungstic acid, sodium salt of silicotungstic acid, copper salt ofsilicotungstic acid, gold salt of silicotungstic acid, palladium salt ofsilicotungstic acid, gallium salt of silicotungstic acid, lithium saltof phosphotungstic acid, sodium salt of phosphotungstic acid, coppersalt of phosphotungstic acid, gold salt of phosphotungstic acid,palladium salt of phosphotungstic acid, gallium salt of phosphotungsticacid, lithium salt of phosphomolybdic acid, sodium salt ofphosphomolybdic acid, copper salt of phosphomolybdic acid, gold salt ofphosphomolybdic acid, palladium salt of phosphomolybdic acid, galliumsalt of phosphomolybdic acid, lithium salt of silicomolybdic acid,sodium salt of silicomolybdic acid, copper salt of silicomolybdic acid,gold salt of silicomolybdic acid, palladium salt of silicomolybdic acid,gallium salt of silicomolybdic acid, lithium salt ofsilicovanadotungstic acid, sodium salt of silicovanadotungstic acid,copper salt of silicovanadotungstic acid, gold salt ofsilicovanadotungstic acid, palladium salt of silicovanadotungstic acid,gallium salt of silicovanadotungstic acid, lithium salt ofphosphovanadotungstic acid, sodium salt of phosphovanadotungstic acid,copper salt of phosphovanadotungstic acid, gold salt ofphosphovanadotungstic acid, palladium salt of phosphovanadotungsticacid, gallium salt of phosphovanadotungstic acid, lithium salt ofphosphovanadomolybdic acid, sodium salt of phosphovanadomolybdic acid,copper salt of phosphovanadomolybdic acid, gold salt ofphosphovanadomolybdic acid, palladium salt of phosphovanadomolybdicacid, gallium salt of phosphovanadomolybdic acid, lithium salt ofsilicovanadomolybdic acid, sodium salt of silicovanado-molybdic acid,copper salt of silicovanadomolybdic acid, gold salt ofsilicovanadomolybdic acid, palladium salt of silicovanadomolybdic acidand gallium salt of silicovanado-molybdic acid.

Among these, preferred are lithium salt of silicotungstic acid, sodiumsalt of silicotungstic acid, copper salt of silicotungstic acid, goldsalt of silicotungstic acid, palladium salt of silicotungstic acid,gallium salt of silicotungstic acid, lithium salt of phosphotungsticacid, sodium salt of phosphotungstic acid, copper salt ofphosphotungstic acid, gold salt of phosphotungstic acid, palladium saltof phosphotungstic acid, gallium salt of phosphotungstic acid, lithiumsalt of phosphomolybdic acid, sodium salt of phosphomolybdic acid,copper salt of phosphomolybdic acid, gold salt of phosphomolybdic acid,palladium salt of phosphomolybdic acid, gallium salt of phosphomolybdicacid, lithium salt of silicomolybdic acid, sodium salt of silicomolybdicacid, copper salt of silicomolybdic acid, gold salt of silicomolybdicacid, palladium salt of silicomolybdic acid, gallium salt ofsilicomolybdic acid, lithium salt of silicovanadotungstic acid, sodiumsalt of silicovanadotungstic acid, copper salt of silicovanadotungsticacid, gold salt of silicovanadotungstic acid, palladium salt ofsilicovanadotungstic acid, gallium salt of silicovanadotungstic acid,lithium salt of phosphovanadotungstic acid, sodium salt ofphosphovanadotungstic acid, copper salt of phosphovanadotungstic acid,gold salt of phosphovanadotungstic acid, palladium salt ofphosphovanadotungstic acid and gallium salt of phosphovanadotungsticacid.

More preferred are lithium salt of silicotungstic acid, sodium salt ofsilicotungstic acid, copper salt of silicotungstic acid, gold salt ofsilicotungstic acid, palladium salt of silicotungstic acid, gallium saltof silicotungstic acid, lithium salt of phosphotungstic acid, sodiumsalt of phosphotungstic acid, copper salt of phosphotungstic acid, goldsalt of phosphotungstic acid, palladium salt of phosphotungstic acid,gallium salt of phosphotungstic acid, lithium salt ofsilicovanadotungstic acid, sodium salt of silicovanadotungstic acid,copper salt of silicovanadotungstic acid, gold salt ofsilicovanadotungstic acid, palladium salt of silicovanadotungstic acid,gallium salt of silicovanadotungstic acid, lithium salt ofphosphovanadotungstic acid, sodium salt of phosphovanadotungstic acid,copper salt of phosphovanadotungstic acid, gold salt ofphosphovanadotungstic acid, palladium salt of phosphovanadotungstic acidand gallium salt of phosphovanadotungstic acid.

The amount of the heteropolyacid and/or heteropolyacid salt supported ispreferably from 5 to 100 mass %, more preferably from 15 to 70 mass %,based on the entire weight of the support. If the heteropolyacid saltcontent is less than 5 mass %, the active component content in thecatalyst is too small and the activity per unit mass of the catalyst maydisadvantageously decrease. If the heteropolyacid salt content exceeds100 mass %, the effective pore volume decreases and, as a result, theeffect owing to the increase in the supported amount may not be broughtout and at the same time, coking is liable to occur to seriously shortenthe catalyst life or the heteropolyacid on the support surface may beseparated.

The support for use in the catalyst of the present invention is notparticularly limited and any material may be used insofar as it is aporous substance. Examples thereof include silica, diatomaceous earth,montmorillonite, titania, activated carbon, silica alumina, alumina,magnesia, niobia and zirconia. Among these, preferred are silica,diatomaceous earth, silica alumina and alumina. The particle size isalso not particularly limited. The particle size is preferably from 0.5to 50 mm and in the case of use in a fixed bed, this is preferably from2 to 10 mm, more preferably from 3 to 7 mm.

The specific surface area of the support is not particularly limited andthis is preferably from 10 to 500 m²/g, more preferably from 50 to 350m²/g, and most preferably from 100 to 300 m²/g.

The pore volume of the support is not particularly limited and this ispreferably from 0.1 to 3.0 ml/g, more preferably from 0.5 to 2.0 ml/g.

The present invention (II) is described below. The present invention(II) is a production process of the supported catalyst of the presentinvention (I).

In the process of the present invention (II), the kinematic viscosity ofthe heteropolyacid and/or heteropolyacid salt solution at 40° C. is from2.0 to 15.0 cSt, preferably from 3.0 to 12.0 cSt, more preferably from4.5 to 10.0 cSt. If the kinematic viscosity is less than 2.0 cSt, theabsorption into the support rapidly proceeds and the heteropolyacidand/or heteropolyacid salt cannot be homogeneously supported in thesurface layer region of the support, whereas if the kinematic viscosityexceeds 15.0 cSt, the absorption into the support proceeds very slowlyand the heteropolyacid and/or heteropolyacid salt solution may not becompletely impregnated. As long as the kinematic viscosity at 40° C. isin the range from 2.0 to 15.0 cSt, the temperature of the heteropolyacidand/or heteropolyacid salt solution may be changed.

The method for measuring the kinematic viscosity is not particularlylimited and any known method may be used. The kinematic viscosity ispreferably measured by a Cannon-Fenske viscometer. The method formeasuring the kinematic viscosity by a Cannon-Fenske viscometer isdescribed in JIS Handbook Kagaku Bunseki (JIS Handbook ChemicalAnalysis), compiled by Japanese Standards Association, issued byJapanese Standards Association, 1st ed., 1st imp., page 443 (Apr. 20,1992).

The production process of a supported catalyst of the present invention(II) comprises a first step of dissolving a heteropolyacid and/or aheteropolyacid salt in a solvent corresponding to 10 to 40 vol % of theliquid absorption amount of a support to obtain a heteropolyacid and/orheteropolyacid salt solution having a kinematic viscosity of 2.0 to 15.0cSt (at 40° C.), a second step of impregnating a support with theheteropolyacid and/or heteropolyacid salt solution obtained in the firststep to obtain a heteropolyacid and/or heteropolyacid salt-impregnatedsupport, and a third step of drying the heteropolyacid and/orheteropolyacid salt-impregnated support obtained in the second step toobtain a heteropolyacid and/or heteropolyacid salt-supported catalyst.

In the first step, a heteropolyacid and/or a heteropolyacid salt isdissolved in a solvent to obtain a heteropolyacid and/or heteropolyacidsalt solution having a kinematic viscosity of 2.0 to 15.0 cSt (at 40°C.). The solvent is used in an amount corresponding to 10 to 40 vol % ofthe liquid absorption amount of a support. If the amount of the solventis less than 10 vol % of the liquid absorption amount of a support, theheteropolyacid and/or heteropolyacid salt may not be completelydissolved, whereas if it exceeds 40 vol %, the heteropolyacid and/orheteropolyacid salt may be absorbed even into the inside of the support.

In the second step, a support is impregnated with the heteropolyacidand/or heteropolyacid salt solution obtained in the first step to obtaina heteropolyacid and/or heteropolyacid salt-impregnated support. In thiscase, the support may be a catalyst precursor having supported thereonother metal component or the like. More specifically, on a supporthaving supported on the surface thereof a metal such as palladium, theheteropolyacid and/or heteropolyacid salt may be supported to lie on themetal.

In the third step, the heteropolyacid and/or heteropolyacidsalt-impregnated support obtained in the second step is dried to obtaina heteropolyacid and/or heteropolyacid salt-supported catalyst. Thetiming of starting the drying subsequently to the impregnation treatmentgreatly varies depending on the size of support and the kinematicviscosity of heteropolyacid and/or heteropolyacid salt. However, if thesupport after the impregnation is left standing as it is, theheteropolyacid and/or heteropolyacid salt may be absorbed into theinside of the support, therefore, the support is preferably driedimmediately after the impregnation.

The drying is performed, for example, in a hot air stream by using anair-blasting drier or in an inert gas stream in a drying room. Forexample, the drying can be performed in a stream of nitrogen or carbondioxide. Depending on the case, the drying is performed under reducedpressure, preferably at 0.01 to 0.08 MPa.

The residual solvent content after the drying is preferably 10 mass % orless. If the solvent remains in the catalyst, the heteropolyacid and/orheteropolyacid salt may be absorbed even into the inside of the support.After the drying, the catalyst is suitably cooled to an ambienttemperature in a desiccator so as not to absorb moisture.

If desired, the supported catalyst after the drying in the third stepmay be treated with a gas containing a reducing gas. In the case ofreducing the catalyst, the reduction may be performed by using a gaseousreducing agent. The reducing temperature is usually from 40 to 350° C.,preferably from 70 to 200° C. In general, the reduction is preferablyperformed by using a reducing agent diluted with an inert gas containingfrom 0.01 to 80 vol %, preferably from 0.5 to 50 vol %, of a reducingagent. Examples of the inert gas which is used include nitrogen, carbondioxide and a rare gas. Suitable examples of the reducing agent includehydrogen, methanol, formaldehyde, ethylene, propylene, isobutylene,butylene and other olefins.

However, if the temperature at the drying or reducing treatment afterthe heteropolyacid and/or heteropolyacid salt is supported exceeds about350° C., the skeleton of the heteropolyacid may be broken.

In the supported catalyst obtained as above, the amount of theheteropolyacid and/or heteropolyacid salt supported can be simplycalculated by subtracting the weight of support from the weight ofcatalyst obtained after drying. The amount supported can be more exactlydetermined by a chemical analysis such as induction coupled plasmaemission spectroscopic analysis (ICP), fluorescent X-ray analysis andatomic absorption analysis.

The solvent which can be used in the first step is not particularlylimited and any solvent may be used as long as it can homogeneouslydissolve or suspend the desired heteropolyacid and/or heteropolyacidsalt. An organic solvent or the like which can be easily removed bydrying after the impregnation treatment is used. The solvent ispreferably a polar solvent. Examples of the polar solvent include alower aliphatic carboxylic acid and a lower aliphatic alcohol. Specificexamples thereof include acetic acid, methanol and ethanol. In thissolvent, water may be contained. Also, a water content derived from thehydrate of heteropolyacid may be contained.

The present invention (III) is described below. The present invention(III) is a process for producing a compound by using the supportedcatalyst of the present invention (I).

The supported catalyst of the present invention (I) can be used for areaction system containing a heteropoly-acid and/or a heteropolyacidsalt as the catalyst component. Examples of the reaction system includea surface reaction and a diffusion-controlled reaction. Specificexamples thereof include an isomerization reaction (see, JapaneseUnexamined Patent Publication No. 2002-105001 (JP-A-2002-105001)), anoxidation reaction (see, JP-A-7-89896 and Japanese Unexamined PatentPublication No. 2000-308830 (JP-A-2000-308830)), a hydration reaction(see, JP-A-11-322646), a dehydrogenation reaction (see, JapaneseUnexamined Patent Publication No. 2001-232207 (JP-A-2001-232207)), anether producing reaction (see, Japanese Unexamined Patent PublicationNo. 7-76540 (JP-A-7-76540)), an esterification reaction (see,JP-A-11-263748 and JP-A-9-118647), a conversion reaction (see, JapaneseUnexamined Patent Publication No. 2001-29789 (JP-A-2001-29789)), anacylation reaction (see, Japanese Unexamined Patent Publication No.10-237020 (JP-A-10-237020)), a Ritter reaction (see, Japanese UnexaminedPatent Publication No. 10-175933 (JP-A-10-175933)) and/or an alkylationreaction (see, Japanese International Application Domestic PublicationNo. 10-508300 (JP-A-10-508300)). Among these, preferred are an oxidationreaction and an esterification reaction.

Examples of the oxidation reaction include a reaction of synthesizing anacetic acid from ethylene and oxygen in the presence of a catalystcontaining at least one compound selected from (a) metal palladium and(b) a heteropolyacid or a salt thereof (see, JP-A-7-89896).

Examples of the esterification reaction include a reaction ofsynthesizing a corresponding ester from a lower aliphatic carboxylicacid and an olefin in the presence of a heteropolyacid and/orheteropolyacid salt catalyst supported on a siliceous support (see,Japanese Unexamined Patent Publication No. 11-269126 (JP-A-11-269126)and JP-A-11-263748).

The present invention is further illustrated below by referring toexamples and comparative examples, however, these examples are set forthonly to show the outline of the present invention, and the presentinvention is not limited by these examples.

Reagent:

The following reagents were used.

Palladium Acetate:

Produced by Wako Pure Chemical Industries, Ltd.

Aqueous Sodium Tetrachloropalladate Solution:

Produced by N.E. Chemcat Corporation (Pd=20.48 mass %)

Aqueous Chloroauric Acid Solution:

Chloroauric acid produced by N.E. Chemcat Corporation (Au=23.89 mass %)was diluted with distilled water to obtain an aqueous solution of Au=10mass %.

Aqueous Zinc Chloride Solution:

Zinc chloride produced by Wako Pure Chemical Industries, Ltd. wasdissolved in distilled water to obtain an aqueous solution of Zn=5 mass%.

Sodium Metasilicate Nonahydrate:

Produced by Wako Pure Chemical Industries, Ltd.

Aqueous Hydrazine Monohydrate Solution:

Hydrazine monohydrate produced by Wako Pure Chemical Industries Ltd. wasdiluted with distilled water to obtain an aqueous solution ofhydrazine=0.53 g/ml.

Sodium Tellurite:

Produced by Wako Pure Chemical Industries, Ltd.

Telluric Acid:

Produced by Kanto Kagaku

Silicotungstic Acid Hexacosahydrate:

Produced by Nippon Inorganic Colour & Chemical Co., Ltd.

Support:

Synthetic silica was used as the support.

EXAMPLE 1 Production and Evaluation of Catalyst A

An aqueous sodium tetrachloropalladate solution (4.883 g), 4.0 g of anaqueous chloroauric acid solution and 1.08 g of a zinc chloride solutionwere diluted with 38 ml (corresponding to 100 vol % of the liquidabsorption amount of support) of distilled water and thereto, 40.4 g ofa support (spherical, diameter: about 5 mmφ) was added and completelyimpregnated with the solution. The resulting support was added to 80 mlof an aqueous solution containing 8.119 g of sodium metasilicatenonahydrate and left standing for 20 hours. Thereto, 11 ml of an aqueoushydrazine monohydrate solution was added and, after washing with water,the support was dried at 110° C. for 4 hours (Supported Body A).Thereafter, Supported Body A was added to 38 ml (corresponding to 100vol % of the liquid absorption amount of support) of an aqueous solutioncontaining 0.208 g of sodium tellurite, impregnated with the solution,air-dried for 1 hour, washed with water and then dried at 110° C. for 4hours (Supported Body B). Subsequently, Supported Body B was charged ina solution prepared by dissolving 20.704 g of silicotungstic acidhexacosahydrate in 13 ml (corresponding to 35 vol % of the liquidabsorption amount of support) of acetic acid and immediately after theentire solution was absorbed, dried at 110° C. for 4 hours to obtain61.82 g of Catalyst A.

Catalyst A prepared as above was analyzed by EPMA and it was found that95% or more of tungsten was present in the region to a depth of 30% ofthe radius.

In a stainless steel-made reaction tube having an internal diameter of21.4 mm, 5 ml of Catalyst A obtained and 11 ml of a diluting supportwere filled and a reaction was performed at a temperature of 200° C. anda pressure of 0.8 MPaG (gauge pressure) by introducing a mixed gasconsisting of 10% of ethylene, 6% of oxygen, 25% of water and 59% ofnitrogen at a flow rate of 45 Nl/H. The gas produced was cooled andcondensed and the collected reaction solution was analyzed by gaschromatography. As a result, the space time yield of acetic acid was 525g/1H, the acetic acid selectivity was 87.9% and the carbon dioxideselectivity was 5.9%.

COMPARATIVE EXAMPLE 1 Production and Evaluation of Catalyst B

Catalyst B (61.81 g) was obtained by repeating the same operation as inExample 1 except that 38 ml (corresponding to 100 vol % of the liquidabsorption amount of support) of an aqueous solution having dissolvedtherein 20.704 g of silicotungstic acid hexacosahydrate was used at thetime of loading silicotungstic acid.

Catalyst B prepared as above was analyzed by EPMA and found that thetungsten was homogeneously supported in the entire support.

A reaction was performed under the same conditions as in Example 1, as aresult, the space time yield of acetic acid was 489 g/1H, the aceticacid selectivity was 87.9% and the carbon dioxide selectivity was 7.7%.

EXAMPLE 2 Production of Catalyst C

In a solution prepared by dissolving 0.78 g of palladium acetate and10.352 g of silicotungstic acid hexacosahydrate in 6.5 ml (correspondingto 35 vol % of the liquid absorption amount of support) of acetic acid,20.2 g of a support (spherical, diameter: about 5 mmφ) was added andafter impregnating the solution, dried at 110° C. for 4 hours in a drier(Supported Body C). Then, Supported Body C obtained was filled in aglass-made reaction tube having an internal diameter of 40 mm andreduced at a temperature of 200° C. under atmospheric pressure for 3hours by introducing a mixed gas consisting of 50% of nitrogen and 50%of hydrogen at a flow rate of 18 Nl/hr to obtain 29.75 g of Catalyst C.Catalyst C prepared as above was analyzed by EPMA and it was found that95% or more of tungsten was present in the region to a depth of 30% ofthe radius.

Analysis Method of Condensate:

Using an analytical solution prepared by adding 10 ml of distilled waterto a condensate, the analysis was performed by an internal standardmethod.

As the internal standard, 100 μl of 1,4-dioxane was added per 10 ml ofthe analytical solution. The analysis was performed by injecting its 0.3μl portion under the following conditions.

-   1. Acetic Acid    Gas Chromatography:    -   GC-9A, manufactured by Shimadzu Corporation        Column:    -   packed column, 5% Thermon-3000 Shincarbon A, 60 to 80 mesh        (length: 3 m)        Carrier Gas:    -   nitrogen (column flow rate: 2.5 ml/min)        Temperature Conditions:    -   The detector and vaporization chamber were at a temperature of        180° C. and the column temperature was elevated up to 150° C. at        a temperature rising rate of 10° C./min from the initiation of        analysis.        Detector:    -   FID (H₂ pressure: 60 KPa, air pressure: 100 KPa)-   2. Trace By-Products    Gas Chromatography:    -   GC-14B, manufactured by Shimadzu Corporation        Column:    -   capillary column (length: 30 m, internal diameter: 0.25 mm, film        thickness: 0.5 μm)        Carrier Gas:    -   nitrogen (split ratio: 20, column flow rate: 1 ml/min)        Temperature Conditions:    -   The detector and vaporization chamber were at a temperature of        200° C. and the column temperature was kept at 37° C. for 7        minutes from the initiation of analysis, then elevated to 50° C.        at a temperature rising rate of 10° C./min, kept at 50° C. for 4        minutes, thereafter elevated to 150° C. at a temperature rising        rate of 20° C./min, kept at 150° C. for 7 minutes, further        elevated to 230° C. at a temperature rising rate of 20° C./min        and kept at 230° C. for 15 minutes.        Detector:    -   FID (H₂ pressure: 60 KPa, air pressure: 100 KPa)        Analysis Method of Uncondensed Gas:    -   Using an absolute calibration curve method, the analysis was        performed under the following conditions by sampling 50 ml of        the uncondensed gas and passing the entire amount thereof into a        1 ml-volume gas sampler attached to the gas chromatograph.-   1. Oxygen, Nitrogen and Carbon Monoxide    Gas Chromatograph:    -   gas chromatography (GC-12A, manufactured by Shimadzu        Corporation) with a gas sampler (MGS-4, measuring tube: 1 ml)        for Shimadzu gas chromatograph        Column:    -   packed column MS-5A IS, 60 to 80 mesh (length: 3 m)        Carrier Gas:    -   helium (flow rate: 2.5 ml/min)        Temperature Conditions:    -   The detector and vaporization chamber were at a temperature of        110° C., and the column temperature was 70° C. and constant.        Detector:    -   TCD (He pressure: 70 KPa, current: 100 MA, temperature: 110° C.)-   2. Ethan, Carbon Dioxide and Ethylene    Gas Chromatograph:    -   gas chromatography (GC-9A, manufactured by Shimadzu Corporation)        with a gas sampler (MGS-4, measuring tube: 1 ml) for Shimadzu        gas chromatograph        Column:    -   packed column Unibeads IS, 60 to 80 mesh (length: 3 m)        Carrier Gas:    -   helium (flow rate: 40 ml/min)        Temperature Conditions:    -   The detector and vaporization chamber were at a temperature of        100° C. and the column temperature was 60° C. and constant.        Detector:    -   TCD (He pressure: 70 KPa, current: 100 mA, temperature: 100° C.)        Measuring Method of Supported Distribution:        Pretreatment        Resin Embedding:

Cold Embedding Resin No. 105 produced by Marumoto Struers K.K. was usedby mixing thereto a hardening agent for No. 105.

Cutting:

-   -   Cut by Isomet (wet diamond cutter). For the refrigerant, a        solvent in which a heteropolyacid and/or a heteropolyacid salt        does not dissolve, such as hexane, was selected.        Vapor Deposition:    -   Platinum was used as the vapor deposition substance.        Apparatus:    -   JXA-8900 manufactured by JEOL Ltd.        EPMA Analysis        X-Ray Detector:    -   Wavelength dispersion spectroscopy (WDS).

-   Acceleration voltage: 15 kV

-   Irradiation current: 1×10⁻⁷ A    Peak Search Conditions (Tungsten)

-   Spectral crystal: PETH

-   Spectral crystal range: 210 to 240 mm

-   Spectral crystal step: 30 μm

-   Integration time: 200 msec    Measurement Conditions in Plane Analysis (Tungsten)

-   Spectral crystal: PETH

-   Spectral crystal position:    -   223.556 mm (signal), 219.6 mm (background 1), 225.6 mm        (background 2)

-   Measurement point distance:    -   X: 20 μm, Y: 20 μm (the measurement region was appropriately set        to enclose the catalyst)

-   Measurement time: 30 msec×1

-   Scan: stage scan    Data Processing:

(1) A data operation was performed by taking account of background toobtain plane analysis data (background correction).

(2) Lines (9 lines) were drawn by rotating the angle in steps of 20°with respect to the plane analysis data operated in (1) and intensityprofile data were obtained every each line (line analysis).

(3) The entire integral intensity from the support surface to thesupport center was calculated.

(4) The entire integral intensity from the support surface to 30% wascalculated.

(5) From the integral intensity ratio determined in (3) and (4), thesupported distribution was calculated.

INDUSTRIAL APPLICABILITY

As described in the foregoing pages, according to the present invention,a so-called egg shell-type supported catalyst where a heteropolyacidand/or a heteropolyacid salt is present in the surface layer region ofthe support can be obtained and this enables an elevation of useefficiency of the heteropolyacid and/or heteropolyacid salt and, as aresult, a supported catalyst having high activity can be provided.

1. A supported catalyst comprising a support having a support surface,and supported on the support at least one member selected from the groupconsisting of heteropolyacids and heteropolyacid salts, wherein 90 mass% or more of the heteropolyacid and/or heteropolyacid salt is present ina surface layer region that extends from the support surface to adistance from the support surface of 30% toward the midpoint in a crosssection of the support.
 2. The catalyst according to claim 1, whereinthe support is spherical.
 3. A catalyst according to claim 1, whereinthe heteropolyacid is at least one member selected from the groupconsisting of silicotungstic acid, phosphotungstic acid, phosphomolybdicacid, silicomolybdic acid, silicovanadotungstic acid,phosphovanadotungstic acid, phosphovanadomolybdic acid,silicovanadomolybdic acid, phosphomolybdotungstic acid,silicomolybdotungstic acid, silicovanadotungstic acid, borotungsticacid, boromolybdic acid and tungstomolybdoboric acid.
 4. A catalystaccording to claim 1, wherein the heteropolyacid salt is either an oniumsalt of a heteropolyacid or a salt resulting from partially or entirelysubstituting hydrogen atoms of a heteropolyacid by at least one elementselected from metal elements belonging to Groups 1 to 13 in the PeriodicTable, and the heteropolyacid is selected from the group consisting ofsilicotungstic acid, phosphotungstic acid, phosphomolybdic acid,silicomolybdic acid, silicovanadotungstic acid, phosphovanadotungsticacid, phosphovanadomolybdic acid, silicovanadomolybdic acid,phosphomolybdotungstic acid, silicomolybdotungstic acid,silicovanadotungstic acid, borotungstic acid, boromolybdic acid andtungstomolybdoboric acid.
 5. A catalyst according to claim 1, whereinthe support is at least one member selected from the group consisting ofsilica, diatomaceous earth, montmorillonite, titania, activated carbon,silica alumina, alumina, magnesia, niobia and zirconia.
 6. A catalystaccording to claim 1, wherein the support has a particle size of from0.5 to 50 mm.
 7. A catalyst according to claim 1, wherein the supporthas a specific surface area of from 10 to 500 m²/g and a pore volumefrom 0.1 to 3.0 ml/g.
 8. A process for producing a supported catalyst asdescribed in claim 1, comprising the following first to third steps:First Step: a step of dissolving a heteropolyacid and/or aheteropolyacid salt in a solvent corresponding to 10 to 40 vol % of theliquid absorption amount of a support to obtain a heteropolyacid and/orheteropolyacid salt solution having a kinematic viscosity of 2.0 to 15.0cSt (at 40° C.); Second Step: a step of impregnating a support with theheteropolyacid and/or heteropolyacid salt solution obtained in the firststep to obtain a heteropolyacid and/or heteropolyacid salt-impregnatedsupport; and Third Step: a step of drying the heteropolyacid and/orheteropolyacid salt-impregnated support obtained in the second step toobtain a heteropolyacid and/or heteropolyacid salt-supported catalyst.9. A process according to claim 8, wherein the solvent is a polarsolvent.
 10. A process according to claim 9, wherein the polar solventis any one of a lower aliphatic carboxylic acid, a lower aliphaticalcohol or a mixture thereof.
 11. A process, for producing a compound,comprising performing a reaction in the presence of a supported catalystas described in claim
 1. 12. A process according to claim 11, whereinthe reaction is at least one reaction selected from the group consistingof an isomerization reaction, an oxidation reaction, a hydrationreaction, a dehydrogenation reaction, an ether-producing reaction, anesterification reaction, a conversion reaction, an acylation reaction, aRifler reaction and an alkylation reaction.
 13. A process according toclaim 11 or 12, wherein a lower aliphatic olefin and an oxygen arereacted to produce a lower aliphatic carboxylic acid.
 14. A processaccording to claim 13, wherein the reaction is performed in the presenceof water.
 15. A process according to claim 11 or 12, wherein a lowerolefin and a lower aliphatic carboxylic acid are reacted to produce alower aliphatic carboxylic acid ester.
 16. A process according to claim15, wherein the reaction is performed in the presence of water.